I need an internal HDD for storage/media etc (I have an SSD for the OS) to replace my Seagate; I do need 1 TB, but not more. The biggest program I'd use it for is Adobe Photoshop CS4. So looks like the main differentiating features are RPM (5400/5900/7200), bus speed (3GB/s or 6GB/s) and cache (16/32/64 mb). How much of a difference do each of these make for a non-OS hard-drive? Obviously cost is a factor, and I was hoping to stay closer to $100 than $150. One Samsung costs $129, for 5400, 3gb/s, 32mb, while another costs $109 at 7200; this Seagate is $114, while this WD Blue at $99 seems great with good reviews at Amazon, but not so good on Newegg. So again, which of these parameters is more important than the other?